1. Field of the Invention
This invention relates to memories, and more particularly, to the act of writing information to a memory.
2. Description of the Related Art
Computer systems utilize varying types of memory within a memory hierarchy to store data needed to conduct operations. Various types of memory can be separated into a hierarchy, with hard disk drives at the lower end of the hierarchy, main memory (typically dynamic random access memory, or DRAM) somewhere in the middle, cache memories near the top, and registers at the very top. Each of these various types of memory provides varying levels of speed. For example, hard disk drives, typically used for long term storage, have the slowest access times. At the other end of the spectrum, registers, which provide temporary storage of data during the execution of instructions, require very fast access times for both reads and writes.
The various types of memory on the access hierarchy have different mechanisms for reading and writing. For example, some memories that do not require fast access times may have only a single access port, through which data can be written to or read from the memory. Other memories that require fast access times, such as register files, may include a number of different read and write ports. This is particularly true for register files implemented in pipelined microprocessors, superscalar microprocessors, and combinations thereof, where multiple reads and writes may be required with each machine cycle. Since, in many embodiments, the requirement for the number of reads and writes per machine cycle drives the number of required read and write ports, achieving higher performance in processor in particular (and a computer system in general) may result in the need for greater numbers of both.